Its now easier to move FSMO roles with Powershell from the 2012 machine.
1) Login to dc2-win2012 and open powershell as administrator
2) Move-ADDirectoryServerOperationMasterRole -Identity “DC2-win2012” -OperationMasterRole 0,1,2,3,4
3) Select yes to all 5 roles
4) run netdom query FSMO to check the roles

At the step when I open ADSI Edit, the default naming context points to the old DC, not the new one as shown above.

Also, if I jump to the next step and try to open “Active directory Domains & Trusts” on the old DC, I get “You cannot modify domain of trust information because a primary domain controller (PDC) emulator cannot be contacted”.

All previous steps were successful: “Schema Master”, “PDC”, “RID”, and “Infrastructure Master” have been transferred.

Your blog and this answer show that MS really missed the boat on managing the FSMO roles. While doable in the GUI you have to go to a lot of different locations to do so. NTDSUTIL provides a single location to manage these roles.

Thanks so much ! I need to move my DC because of changing hardware. And I am installing 2013 Exchange and I had errors from the installer regarding schema changes needed. Followed your procedure and I can now switch off the old 2008 Server! Thank you thank you thank you !

will these steps work even if the current FSMO holder (2003 PDC) has died? Example- 2003 and 2012 domain controllers / full active directory / dns etc – 2003 dies / can the 2012 gui steps be performed if the 2003 machine is unable to respond to the transfer?

Having performed all above and getting the correct response when I check the FSMO roles to see that the new 2012-r2 server has all the roles assigned
If I reboot the old 2008-r2 DC no one can logon to the network.
I assume this is more DNS than an AD issue?
Ideally though not best practice I only need 1 AD server (2012-r2)